The research in this Asthma and Allergic Diseases Center deals with cell-mediated immune responsiveness in atopy. Significant abnormalities have been observed in both specific and non-specific parameters of cell-mediated immunity in patients with allergic eczema as well as in patients with immunodeficiency disorders characterized by augmented IgE antibody production. These abnormalities may relate to the basic pathophysiology of atopic diseases. To evaluate cell-mediated immune responsiveness to pollen allergens in atopic subjects, we studied the DNA synthetic responses of their cultured lymphocytes to purified ragweed antigens E, K, and Ra-3. Unexpectedly, we found comparable proliferative responses with lymphocytes from treated and untreated ragweed-sensitive patients and from normal nonatopic, newborn, and aggamaglobulinemic subjects. Studies with purified lymphocyte subpopulations indicate that only T cells proliferate in response to these agents. These findings suggest that ragweed pollens are either ubiquitous and lead to cell-mediated responsiveness in all subjects with intact cell-mediated immunity, or that they may have mitogenic properties in addition to their known antigenic properties. The proposed research will continue to investigate responses of lymphocyte subpopulations and of immune effector cells (monocytes, polymorphonuclear neutrophils) from atopic subjects to allergens and to non-specific stimuli. In addition to continued evaluation of the lymphocyte subpopulations stimulated by purified ragweed allergens, studies will be conducted to determine whether soluble factors released into supernatants of such cultures regulate IgE antibody synthesis. Other studies are designed to detect T suppressor cell populations (for immunoglobulin E biosynthesis) in normal subjects and any possible deficiency that may exist in atopics. Finally, studies of abnormalities of immune effector function in atopic patients will be extended to characterize serum inhibitors of chemotaxis found in these patients and to examine chemotactic lymphokine production in response to purified pollen allergens.